Electrode orientation and parallelism adjustment mechanism for plasma processing systems

ABSTRACT

A mechanism for adjusting an orientation of an electrode in a plasma processing chamber is disclosed. The plasma processing chamber may be utilized to process at least a substrate, which may be inserted into the plasma processing chamber in an insertion direction. The mechanism may include a support plate disposed outside a chamber wall of the plasma processing chamber and pivoted relative to the chamber wall. The support plate may have a first thread. The mechanism may also include an adjustment screw having a second thread that engages the first thread. Turning the adjustment screw may cause translation of a portion of the support plate relative to the adjustment screw. The translation of the portion of the support plate may cause rotation of the support plate relative to the chamber wall, thereby rotating the electrode with respect to an axis that is orthogonal to the insertion direction.

RELATED APPLICATIONS

The present invention claims priority under 35 U.S.C. 119(e) to acommonly owned provisionally filed patent application entitled“ELECTRODE ORIENTATION/PARALLELISM ADJUSTMENT MECHANISM FOR PLASMAPROCESSING SYSTEMS,” U.S. Application No. 61/027,372, Attorney DocketNo. P1809P/LMRX-P155P1, filed Feb. 8, 2008, by inventor James E. Tappan;and a commonly owned provisionally filed patent application entitled “AFLOATING COLLAR CLAMPING DEVICE FOR AUTO-ALIGNING NUT AND SCREW INLINEAR MOTION LEADSCREW AND NUT ASSEMBLY,” U.S. Application No.61/027,405, Attorney Docket No. P1806P/LMRX-P154P1, filed Feb. 8, 2008,by inventor James E. Tappan, all of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

In plasma processing, the shrinking feature sizes and the implementationof new materials in the next generation of device fabrication have putnew requirements on plasma processing equipment. The smaller devicefeatures, larger substrate size, and new processing techniques(involving multi-step recipes, such as for dual-damascene etch) haveincreased the challenge to maintain good uniformity across the wafer forbetter device yields.

In capacitively coupled RF plasma reactors, the electrode opposite tothe substrate electrode is generally called the upper electrode. Theupper electrode could be grounded, or have one or more radio frequency(RF) power sources attached to it. The substrate electrode is generallycalled the lower electrode. A mechanical arrangement for a lowerelectrode in a capacitively coupled plasma processing chamber mayinvolve cantilevering the assembly that includes the lower electrodefrom a side of the chamber. This cantilevered lower electrode can be afixed distance from the upper electrode or can be designed for avariable distance from the upper electrode. In either case, parallelismof one electrode surface to the other is generally a critical mechanicalparameter that can affect the process performance on the wafer.

Due to added complexity, many capacitively coupled RF plasma reactorsforgo the feature of precise parallelism adjustment between electrodesand rely on tight manufacturing tolerances of the assembly components tokeep parallelism within acceptable limits. This approach typically addscost to those components and may limit the ultimate parallelismspecification that can be achieved. Other arrangements include slots orclearance holes in mating parts allowing free play to adjust parallelismduring assembly. This approach is time consuming and usually requiresrepetitive processes to achieve the correct configuration. The approachmay also require the plasma processing system to be disassembled to someextent to adjust the necessary components. Other methods attempt toprovide a means for adjustment, but may have no direct means tocorrelate the amount of adjustment to the actual effect on at least oneof the electrodes. As a result, such methods may also require iterativeprocesses to dial in parallelism. Some of these methods are alsovulnerable to shifting of the adjustment over time due to vibrations,such as shipping loads.

SUMMARY

An embodiment of the invention relates to a mechanism for adjusting anorientation of an electrode in a plasma processing chamber. The plasmaprocessing chamber may be utilized to process at least a substrate,which may be inserted into the plasma processing chamber in an insertiondirection. The mechanism may include a support plate disposed outside achamber wall of the plasma processing chamber and pivoted relative tothe chamber wall. The support plate may have a first thread. Themechanism may also include an adjustment screw having a second threadthat engages the first thread. Turning the adjustment screw may causetranslation of a portion of the support plate relative to the adjustmentscrew. The translation of the portion of the support plate may causerotation of the support plate relative to the chamber wall, therebyrotating the electrode with respect to an axis that is orthogonal to theinsertion direction.

The above summary relates to only one of the many embodiments of theinvention disclosed herein and is not intended to limit the scope of theinvention, which is set forth in the claims herein. These and otherfeatures of the present invention will be described in more detail belowin the detailed description of the invention and in conjunction with thefollowing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings and in whichlike reference numerals refer to similar elements and in which:

FIG. 1A shows a partial perspective view of a plasma processing chamberincluding an adjustment mechanism for adjusting the orientation of alower electrode in the plasma processing chamber in accordance with oneor more embodiments of the present invention.

FIG. 1B shows a partial side view of the plasma processing chamberillustrating a first rotation (or the pitch) of the lower electrode inaccordance with one or more embodiments of the present invention.

FIG. 1C shows a partial rear view of the plasma processing chamberillustrating a second rotation (or the roll) of the lower electrode inaccordance with one or more embodiments of the present invention.

FIG. 1D shows a partial side view of the adjustment mechanism inaccordance with one or more embodiments of the present invention.

FIG. 1E shows a partial perspective view of a pitch adjustment userinterface of the adjustment mechanism in accordance with one or moreembodiments of the present invention.

FIG. 1F shows a partial exploded view of the adjustment mechanism inaccordance with one or more embodiments of the present invention.

FIG. 1G shows a perspective view of a roll adjustment cam of theadjustment mechanism in accordance with one or more embodiments of thepresent invention.

FIG. 1H shows a partial perspective view of a roll adjustment userinterface of the adjustment mechanism in accordance with one or moreembodiments of the present invention.

FIG. 1I, another view of FIG. 1A, shows a partial perspective view ofthe plasma processing chamber including an adjustment mechanism foradjusting the orientation of the lower electrode in the plasmaprocessing chamber in accordance with one or morc embodiments of thepresent invention.

FIG. 1J, another view of FIG. 1B, shows a partial side view of theplasma processing chamber illustrating the first rotation (or the pitch)of the lower electrode in accordance with one or more embodiments of thepresent invention.

FIG. 1K, another view of FIG. 1C, shows a partial rear view of theplasma processing chamber illustrating the second rotation (or the roll)of the lower electrode in accordance with one or more embodiments of thepresent invention.

FIG. 1L, another view of FIG. 1D, shows a partial side view of theadjustment mechanism in accordance with one or more embodiments of thepresent invention.

FIG. 1M, another view of FIG. 1E, shows a partial perspective view ofthe pitch adjustment user interface of the adjustment mechanism inaccordance with one or more embodiments of the present invention.

FIG. 1N, another view of FIG. 1F, shows a partial exploded view of theadjustment mechanism in accordance with one or more embodiments of thepresent invention.

FIG. 1O, another view of FIG. 1G, shows a perspective view of the rolladjustment cam of the adjustment mechanism in accordance with one ormore embodiments of the present invention.

FIG. 1P, another view of FIG. 1H, shows a partial perspective view ofthe roll adjustment user interface of the adjustment mechanism inaccordance with one or more embodiments of the present invention.

DETAILED DESCRIPTION

The present invention will now be described in detail with reference toa few embodiments thereof as illustrated in the accompanying drawings.In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present invention. Itwill be apparent, however, to one skilled in the art, that the presentinvention may be practiced without some or all of these specificdetails. In other instances, well known process steps and/or structureshave not been described in detail in order to not unnecessarily obscurethe present invention.

One or more embodiments of the invention relate to a mechanism foradjusting electrode-to-electrode parallelism in a plasma processingsystem. The mechanism may separately adjust the orientation/rotation ofthe lower electrode in the pitch (front to back) and roll (side to side)directions. The mechanism may include low-cost, simple parts thatcollectively accomplish the high-precision adjustment for parallelismwith a low combined cost.

The mechanism may allow electrode orientation/parallelism adjustment totake place while the system is under vacuum, at atmosphere, and/orin-situ, since the user interfaces of the mechanism are disposed outsidethe plasma processing chamber. The mechanism may also allow theadjustment to be made with minimum or no disassembly of the plasmaprocessing system.

The mechanism may enable precise electrode orientation/parallelismadjustment. Precise adjustment of parallelism with accuracy up to 0.01mm can easily be achieved. The mechanism may also include calibratedindex marks to give clear feedback of the amount of adjustment, therebyeliminating the need for iterative adjusting and measuring.

The mechanism may also enable locking electrode orientation/parallelismsettings. Once an adjusted electrode orientation/parallelism setting issecurely locked down, the setting should stay unchanged through normalvibrations and shipping loads.

By utilizing low-cost parts and allowing fast adjustment-locking ofparallelism to a precise level, the mechanism may reducing the need fortight manufacturing tolerances on major components and maycost-effectively optimize process performance with regard to electrodeparallelism.

One or more embodiments of the invention relate to a plasma processingsystem that includes the electrode orientation/parallelism adjustmentmechanism discussed above and further discussed in the examples below.

The features and advantages of the present invention may be betterunderstood with reference to the figures and discussions that follow.

FIG. 1A shows a partial perspective view of a plasma processing chamber198 including a mechanism 100 for adjusting the orientation of a lowerelectrode 110 in accordance with one or more embodiments of the presentinvention. For optimizing the processing yield in plasma processingchamber 198, the electrode-to-electrode parallelism between an upperelectrode 198 and lower electrode 110 may be ensured by adjusting theorientation of lower electrode 110.

Mechanism 100 may include a tunnel support plate 102 (support plate 102)coupled with lower electrode 110 through a cantilever 114 and a biashousing 112. Mechanism 100 may also include a pitch adjustment screw 106for adjusting the pitch of lower electrode 110; the pitch of lowerelectrode 110 is illustrated in the example of FIG. 1B. Mechanism 100may also include a roll adjustment cam 104 for adjusting the roll oflower electrode 110; the roll of lower electrode 110 is illustrated inthe example of FIG. 1C.

FIG. 1B shows a partial side view of plasma processing chamber 198illustrating a first rotation 192 (pitch 192) in accordance with one ormore embodiments of the present invention. Mechanism 100 may facilitatethe adjustment of first rotation 192 (pitch 192) of lower electrode 110with respect to a pitch axis 118. Pitch axis 118 is substantiallyorthogonal to a substrate insertion direction 116, in which a substratemay be inserted into plasma processing chamber 198.

FIG. 1C shows a partial rear view of plasma processing chamber 198illustrating a second rotation 194 (roll 194) in accordance with one ormore embodiments of the present invention. Mechanism 100 may facilitatethe adjustment of second rotation 194 (roll 194) of lower electrode 110with respect to a roll axis 120. Roll axis 120 is substantially parallelto substrate insertion direction 116

FIG. 1D shows a partial side view of mechanism 100 in accordance withone or more embodiments of the present invention. In mechanism 100,support plate 102 may be disposed outside a chamber wall 126 of plasmaprocessing chamber 198 (shown in the example of FIG. 1A). Support plate102 may be pivoted relative to chamber wall 126, for example, by pivot122 and/or another pivot mechanism at a portion 138, e.g., the upperportion, of support plate 102. The support plate may have a thread 146that may engage a thread 128 of pitch adjustment screw 106. Accordingly,turning pitch adjustment screw 106 may cause the translation of aportion 140 (e.g., the lower portion) of support plate 102 relative topitch adjustment screw 106 in an outward direction 142 or an inwarddirection 144. The translation of portion 140 of support plate 102 maycause rotation of support plate 102 with respect to chamber wall 126.Since support plate 102 is coupled with lower electrode 110, therotation of support plate 102 following direction 142 or 144 maysubstantially cause rotation of lower electrode 1.10 with respect topitch axis 118. The precision of threads 146 and 128 may enable theamount of rotation 192 of lower electrode 110 to be stably and preciselyadjusted.

Mechanism 100 may also include a lift plate 124 disposed between chamberwall 126 and support plate 102. Mechanism 100 may also include one ormore bearings, such as bearings 134 and 136, coupled with lift plate 124and chamber wall 126. The one or more bearings may facilitate and/orguide the movement of support plate 102 relative to chamber wall 126(e.g., translation in direction 142 or 144, and/or translation in adirection perpendicular to direction 142 or 144), for smooth and preciseadjustment of rotation 192 of lower electrode 110.

Mechanism 100 may also include a clamping mechanism, for example,including a split clamp 132 and a clamp screw 130, for locking/fasteningpitch adjustment screw 106 to support plate 102, thereby preventingpitch adjustment screw 106 from rotation and translation. For example,it may be desirable to have pitch adjustment screw 106 clamped after thepitch adjustment for lower electrode 110 has been completed for lockingdown the setting. Split clamp 132 may surround pitch adjustment screw106. Clamp screw 130 may be disposed substantially perpendicular topitch adjustment screw 106 and may be coupled with split clamp 132 forpressing split clamp 132 to secure pitch adjustment screw 106. A toolslot may be implemented on clamp screw 130 for facilitating the user torigidly lock/clamp the entire mechanism 100 once the pitch adjustmenthas been completed.

FIG. 1E shows a partial perspective view of a user interface 182 ofmechanism 100 for adjusting pitch 192 of lower electrode 110 inaccordance with one or more embodiments of the present invention. Userinterface 182 may include at least one pitch adjustment index 150implemented on support plate 102 for providing visual feedbackconcerning pitch adjustment to a user. User interface 182 may alsoinclude an indicator 148 implemented on pitch adjustment screw 106 forcooperating with pitch adjustment index 150 to indicate the amount ofpitch adjustment. Alternatively or additionally, a pitch adjustmentindex may be implemented on pitch adjustment screw 106, and/or anindicator may be implemented on support plate 102.

Mechanism 100 may also include a pitch adjustment clamp screw 106Acoupled with and at least partially inserted into pitch adjustment screw106. Pitch adjustment clamp screw 106A may secure pitch adjustment screw106 to support plate 102. A tool slot 186 may be implemented on a pitchadjustment clamp screw 106A for facilitating the user to rigidlylock/clamp pitch adjustment screw 106 and/or the entire mechanism 100once the pitch adjustment has been completed.

In one or more embodiment, pitch adjustment screw 106 may be coupledwith an automatic control mechanism for controlling the pitch adjustmentand/or calibration in an automatic fashion. The automatic controlmechanism may include, for example, a sensor, a control logic unit, anda motor (e.g., a high-resolution step motor).

FIG. 1F shows a partial exploded view of mechanism 100 in accordancewith one or more embodiments of the present invention. Mechanism 100 mayinclude a roll adjustment bar 154 coupled with roll adjustment cam 104and may be actuated by roll adjustment cam 104. Roll adjustment bar 154may be coupled with support plate 102 by pitch adjustment screw 106.Accordingly, through roll adjustment bar 154, roll adjustment cam 104may actuate translation of portion 140 of support plate 102. As aresult, support plate 102 may rotate relative to chamber wall 126 withrespect to pivot 122 (shown in the example of FIG. 1D), thereby causingrotation 194 (roll 194) of lower electrode 110 shown in the example ofFIG. 1C.

Constrained and guided by slot 160 in lift plate 124, roll adjustmentbar 154 may translate along a long axis 164 of roll adjustment bar 154in direction 166 or 168. Accordingly, the amount of rotation 194 oflower electrode 110 may be stably and precisely adjusted.

Mechanism 100 may also include a roll adjustment lock-down screw 158coupled with roll adjustment cam 104. Roll adjustment lock-down screw158 may lock roll adjustment cam 104 relative to roll adjustment bar 154and may simultaneously lock roll adjustment bar 154 relative to liftplate 124, thereby preventing (further) rotation 194 (roll 194) of lowerelectrode 110. Roll adjustment lock-down screw 158 may be utilized, forexample, after roll adjustment for lower electrode 110 has beencompleted.

Mechanism 100 may also include a washer 162 (e.g., a precision, hardenedwasher) coupled with lift plate 124 for receiving pitch adjustment screw106. Washer 162 may protect lift plate 124 from being damaged by pitchadjustment screw 106. Washer 162 may also provide low friction tofacilitate smooth movement of pitch adjustment screw 106, therebyfurther smoothing and stabilizing the operation of mechanism 100.

FIG. 1G shows a perspective view of roll adjustment cam 104 inaccordance with one or more embodiments of the present invention. Rolladjustment cam 104 may include a portion 172 disposed in aneccentric/offset arrangement with respect to a portion 174 of rolladjustment cam 104, for enabling roll adjustment cam 104 to actuate rolladjustment bar 154 (shown in the example of FIG. 1F). Roll adjustmentcam 104 may be replaced with other replacement roll adjustment cams withdifferent eccentric/offset arrangements for particular actuation effectsthat suit particular roll adjustment needs.

FIG. 1H shows a partial perspective view of a user interface 184mechanism 100 for adjusting roll 194 of lower electrode 110 inaccordance with one or more embodiments of the present invention. Userinterface 184 may include at least one roll adjustment index 178implemented on lift plate 124 for providing visual feedback concerningroll adjustment to a user. User interface 184 may also include anindicator 180 implemented on roll adjustment cam 104 for cooperatingwith roll adjustment index 178 to indicate the amount of rolladjustment. Alternatively or additionally, a roll adjustment index maybe implemented on roll adjustment cam 104, and/or an indicator may beimplemented on lift plate 124. A tool slot 176 may be implemented onroll adjustment cam 104 for facilitating the user to perform the rolladjustment, for example, utilizing a screw driver.

In one or more embodiment, roll adjustment cam 104 and/or pitchadjustment screw 106 may be coupled with an automatic control mechanismfor controlling pitch and/or roll adjustment and/or calibration in anautomatic fashion. The automatic control mechanism may include, forexample, a sensor, a control logic unit, and a motor (e.g., ahigh-resolution step motor).

As can be appreciated from the foregoing, with low-cost parts,embodiments of the invention may allow fast adjustment and locking ofparallelism to a precise level. Accordingly, embodiments of theinvention may reduce the need for costly tight manufacturing toleranceson major components. Advantageously, embodiments of the invention maycost-effectively optimize process performance with regard to electrodeparallelism.

Embodiments of the invention may enable precise electrodeorientation/parallelism adjustment. Embodiments of the invention mayalso include calibrated index marks to give clear feedback of the amountof adjustment. Advantageously, the need for iterative adjusting andmeasuring required in the prior art may be eliminated.

Embodiments of the invention may allow the adjustment of electrodeorientation and/or parallelism to take place while a plasma processingsystem is under vacuum, atmosphere, and/or in-situ, since the userinterfaces are disposed outside the plasma processing chamber.Embodiments of the invention may also allow the adjustment to be madewith minimum or no disassembly of the plasma processing system.Advantageously, system down time may be minimized, and productivity maynot be compromised, while the needs for electrode orientation and/orparallelism adjustment are satisfied.

Embodiments of the invention may also enable locking the settings ofelectrode orientation/parallelism. An adjusted electrodeorientation/parallelism setting may stay unchanged through normalvibrations and shipping loads. Advantageously, the resources (e.g.,labor, time, etc.) required for the re-adjustment of electrodeorientation/parallelism may be minimized.

While this invention has been described in terms of several embodiments,there are alterations, permutations, and equivalents, which fall withinthe scope of this invention. It should also be noted that there are manyalternative ways of implementing the methods and apparatuses of thepresent invention. Furthermore, embodiments of the present invention mayfind utility in other applications. The abstract section may be providedherein for convenience and, due to word count limitation, may beaccordingly written for reading convenience and should not be employedto limit the scope of the claims. It may be therefore intended that thefollowing appended claims be interpreted as including all suchalternations, permutations, and equivalents as fall within the truespirit and scope of the present invention.

1. The mechanism of claim 16, further comprising: an adjustment screwhaving a second thread, the second thread engaging the first thread forpitch adjustment, wherein turning the adjustment screw causes a secondtranslation of a portion of the support plate relative to the adjustmentscrew, the second translation of the portion of the support plateconfigured to cause a second rotation of the support plate inward oroutward relative to the chamber wall, the second rotation of the supportplate configured to cause a second rotation of the first electrode withrespect to a second axis that is orthogonal to the insertion direction.2. The mechanism of claim 1 further comprising a first clamp screwcoupled with the adjustment screw and at least partially inserted intothe adjustment screw, the first clamp screw configured to secure theadjustment screw to the support plate.
 3. The mechanism of claim 2further comprising: a clamp coupled with the adjustment screw; and asecond clamp screw disposed perpendicular to the adjustment screw, thesecond clamp screw coupled with the clamp, the second clamp screwconfigured to press the clamp to fasten the adjustment screw to thesupport plate.
 4. The mechanism of claim 1 further comprising: a firstindex implemented on the support plate for providing visual feedbackconcerning the second rotation of the first electrode; and a firstindicator implemented on the adjustment screw for cooperating with thefirst index to indicate an amount of the second rotation of the firstelectrode.
 5. The mechanism of claim 1 further comprising: a first indeximplemented on the adjustment screw for providing visual feedbackconcerning the second rotation of the first electrode; and a firstindicator implemented on the support plate for cooperating with thefirst index to indicate an amount of the second rotation of the firstelectrode.
 6. The mechanism of claim 1 further comprising: a lift platedisposed between the chamber wall and the support plate, the lift platecoupled with the support plate; and one or more bearings coupled withthe lift plate and coupled with the chamber wall, the one or morebearings configured to guide at least the second translation of theportion of the support plate.
 7. (canceled)
 8. The mechanism of claim 6further comprising a washer coupled with the support plate, the washerconfigured to receive the adjustment screw, the washer furtherconfigured to protect the lift plate from being damaged by theadjustment screw, the washer further configured to smoothen movement ofthe adjustment screw.
 9. (canceled)
 10. (canceled)
 11. (canceled) 12.The mechanism of claim 17 further comprising a lock-down screw coupledwith the cam, the lock-down screw configured to lock the cam to the bar,the lock-down screw further configured to lock the bar to the liftplate.
 13. (canceled)
 14. (canceled)
 15. The mechanism of claim 1further comprising a control unit coupled with the adjustment screw andthe cam, the control unit configured to automatically adjust the firstrotation of the first electrode and the second rotation of the firstelectrode.
 16. A mechanism for adjusting an orientation of a firstelectrode in a plasma processing system, the plasma processing systemconfigured for processing at least a substrate, the plasma processingsystem further including at least a plasma processing chamber, theplasma processing chamber including at least a chamber wall, the firstelectrode positioned inside the plasma processing chamber, the substrateconfigured to be inserted into the plasma processing chamber in aninsertion direction, the mechanism comprising: a support plate coupledwith the first electrode, the support plate having a first thread, thesupport plate disposed outside the chamber wall and pivoted relative tothe chamber wall; and a cam coupled with the support plate, the camconfigured to cause a first translation of a portion of the supportplate relative to the chamber wall, thereby causing a first rotation ofthe support plate relative to the chamber wall, the first rotation ofthe support plate configured to cause a first rotation of the firstelectrode with respect to a first axis that is parallel to the insertiondirection.
 17. The mechanism of claim 16 further comprising: a barcoupled with the cam and coupled with the support plate, the barconfigured to be actuated by the cam; and a lift plate disposed betweenthe chamber wall and the support plate, the lift plate including atleast a slot coupled with the bar, the slot configured to guide andlimit movement of the bar, thereby limiting the rotation of the firstelectrode.
 18. (canceled)
 19. (canceled)
 20. (canceled)